JPS6294247A - Numerically controlled machine tool having halfway stopping function - Google Patents

Abstract

PURPOSE:To obtain a finish of desired dimensions for from the initial workpiece by providing a control part for forbidding the prior reading of a data block, a machine tool stoppage control part, a correction value inputting part, and a correction control part, by means of a setting condition of switch means and a stoppage command code. CONSTITUTION:When there is a stoppage command code G65 after interpreting a data, its specified switch condition is judged and, if it is on, control is stopped since the stoppage command code is effective. After control is stopped, when an operator depresses a backing switch S2 on a control board 35, a grinding wheel is backed by a defined quantity and stopped. Then the operator displays a correction value inputting image plane on a CRT 38 by operating a data writing device 36, and measures the dimension of outside diameter of a workpiece. Since the progress of machining on program is indicated as the stopping position XO of the grinding wheel, the operator inputs a correction values HO relating to the whole stages of finish dimensions and correction values H1-H10 in every stage, and the like, from the data of the stopping position and the measured value. Then, as the operator depresses a switch S3, the grinding wheel returns accurately to the original position where the grinding is stopped, enabling machining to a desired dimension.

Description

[Detailed description of the invention]

[Industrial application field]

The present invention relates to a numerically controlled machine tool that is equipped with an intermediate stop function, corrects finished dimensions from the actually measured outside diameter of a workpiece during machining, and enables accurate machining from the first workpiece.

[Prior art]

Normally, when machining is performed using a numerically controlled machine tool, after the first workpiece has been machined using the numerical control program, the dimensions of the workpiece are measured and the difference between them and the commanded finished dimensions is determined.
Based on the difference, the tool feed position data in the numerical control program was corrected to accurately obtain the desired finished dimensions from the next workpiece. As a result, the first workpiece was wasted. In order to improve this and obtain accurate finished dimensions from the first workpiece, the following method had to be adopted. Automatic operation is stopped in the middle of the machining process, and then the machine is switched to manual operation, the tool is retracted, and the dimensions of the workpiece are measured. Then manually return the tool to its original position.
Cuts corresponding to the measured dimensions are made using an assisted operation to produce the desired finished dimensions. Conventionally, this method was used to obtain precision in the finished dimensions of the initial workpiece.

[Problems to be solved by the invention]. However, since all of the tools are moved manually after the machine has temporarily stopped, the machine must be constantly monitored to determine when to stop, which is extremely troublesome. Also,
The data correction performed before the second and subsequent processing has to be performed for each feeding process, making the data correction complicated. Furthermore, in an apparatus that employs a method of pre-reading data blocks of a numerical control program into a buffer register, when the apparatus is temporarily stopped, the next data block has already been read into the buffer register. Therefore, when restarting machining after a temporary stop is automatically performed, there is a problem in that when the control is restarted, it is necessary to start the numerical control program again, which complicates the work. The present invention is intended to solve these problems, and its purpose is to automate the temporary suspension of machining operations, correction of data such as finished dimensions, and resumption of control.
To easily obtain highly accurate finished dimensions from the initial workpiece.

[Means to solve the problem]

The structure of the invention for solving the above problems is as follows, and a conceptual diagram thereof is shown in FIG. The present invention comprises: a machine tool H that processes a workpiece with a tool; a drive device F that drives a movable axis of the machine tool I; and a data storage device that stores data necessary to determine the feed position of the tool. C, an input control unit B that pre-reads the data blocks of the numerical control program written in the storage medium E into the buffer register A1 one block at a time, and transfers the data blocks input to the buffer register A1 to the active register Δ2; A numerically controlled machine tool consisting of a control section A that decodes the command word of this data block and controls the drive device F according to the command word and data set in the data storage device C; The data storage device C has a switch means for enabling the function of a stop command code to stop the operation of the machine, and the data storage device C has an area for storing correction data for correcting the feed position of the tool, and When reading the data blocks of the numerical control program written in the Idoku storage medium E into the buffer register A1 block by block, the unit B determines the presence or absence of the stop command code and the set state of the switch means. As a result, when it is determined that the stop command code exists and the setting state of the switch means is such that the function of the stop command code is enabled, the next data block is prohibited from being read ahead. It has a read prohibition control section B1, and the control section A decodes the command word of the active register A2, and as a result,
When the command word is the stop command code and the setting state of the switch means is such that the function of the stop command code is enabled, a stop control unit A3 that stops the operation of the numerically controlled machine tool; By the stop control unit A3,
a correction value input section A5 for inputting correction values necessary for correcting the finished dimensions of the workpiece into the data storage device C while the operation is stopped; A command signal s1 to start reading of the data is output to the input control unit B, the tool feeding position is corrected based on the correction value input to the data storage device C, and control of the machine tool is restarted. The control unit A4 is characterized in that it has a control unit A4.

[Effect]

The operator creates a numerical control program in which a stop command code is inserted into the part of the machining cycle where the operation is to be stopped. Then, this program is set in the numerical control device and the switch means is set to enable the stop command code. The input control unit normally reads the numerical control program written in the storage medium into the buffer register one data block at a time. At this time, the prefetch prohibition control section
The presence or absence of a stop command code is determined from the setting state of the switch means and the read command word. As a result, the setting state of the switch means is such that the stop command code is valid;
When the presence of the stop command code is determined, pre-reading of the data block is prohibited during the next data block read cycle. The stop control unit decodes the data in the active register, and when the result is a stop command code, and the switch means is set to enable the command code, it stops the operation of the machine tool. Thereafter, the tool is retracted by a certain amount manually or preferably automatically by retraction means. After that, the operator measures the outer diameter of the workpiece. The correction value input section inputs into the data storage device a correction value necessary for correcting the finished dimension based on the machining error in the state determined from the theoretical value and the measured value at that time. Thereafter, the operator returns the tool to the position where the machining operation was stopped, either manually or, preferably, by means of advancing means. Thereafter, the correction control unit is activated, reads data from the data block next to the stop instruction code into the buffer register, and restarts the machining operation according to the newly determined tool feed position based on the correction value input to the data storage device. The machining operation continues. As a result, the workpiece can be machined to the corrected finished dimensions, so that desired machining accuracy can be obtained from the initial workpiece. When machining the second and subsequent workpieces, the switch means is set to disable the stop command code. Then, the stop instruction code is skipped when being read into the buffer register, or its function is disabled when it is input to the active register. therefore,
The machining operation is not stopped, and the tool feed control is performed in consideration of the i value set in the data storage device. As a result, the second and subsequent workpieces are machined with the same machining accuracy as the first workpiece.

【Example】

Embodiments of the present invention will be described below based on the drawings. In FIG. 2, 10 is a grinding machine, and 20 is a numerical control device. The grinding machine 10 includes a grindstone table 11 on which a grinding wheel G is supported, and a workpiece table 13 on which a workpiece W is placed. The grindstone head 11 and workpiece table 13 are
They are moved by servo motors 12 and 14, each of which is rotationally driven by a drive circuit 16, 17. Note that 15 is an end face sizing device for positioning the workpiece W in the axial direction. The numerical control device 20 includes a central processing unit 21, a storage device 22, a pulse generation circuit 23, and interfaces 26 and 27.
, 28, and command pulses sent from the pulse generation circuit 23 are supplied to the drive circuits 16 and 17. The storage device is provided with a machining data storage area MDA into which data such as tool feed positions and correction values are input. Furthermore, as the registers 29, a first buffer register BFI, a second buffer register BF2, and an active register AR are provided. On the other hand, a display control circuit 37 is connected to the interface 26 and drives a CRT display device 38. The interface 27 also includes a data writing device 36 for inputting and setting data to the storage device 22, a bubble cassette input/output bag opening 34 storing a numerical control program, and operation switches for inputting various operations. A control panel 35 provided therein is connected. Using the CRT display device 38 and data writing device 36, the machined shape of the workpiece is input. The machining dimensions are set in the machining data record tα area MDA based on the input information on the machining shape of the workpiece for each machining stage. The numerical control program that performs machining processing for each machining stage has no actual movement amount data programmed, and M
It is programmed as shown in diagram m7 using parameter salts C40, C10, C11, C12, etc. representing one of the data stored in the DA. The control panel 35 is provided with switch means 41 and 42 that enable the stop command code G65. In addition, there is a start switch S1 for starting the numerical control device 20, a backward switch S2 for reversing the grinding wheel G by a certain amount after a temporary stop, and a reversing switch S2 for moving the grinding wheel G backward until it contacts the original position of the workpiece W. There are provided a forward switch S3 for restarting the numerical control device 20 from that position, and a restart switch S4 for restarting the numerical control device 20 from that position. Next, the operation of the tree numerical control device 20 will be explained. The numerical control program is coded as shown in FIG. 7 and stored in a bubble cassette. Sequence numbers N100 to N106, etc. are programs for machining the first stage of the workpiece, and sequence number N200
~N2O4 etc. are programs for processing the second role. #1 coded in data blocks N100 and N200. #2 indicates the processing step number of the special processing. Details of the first stage processing are shown in FIG. Each feed control is performed for rapid traverse, rough grinding, fine grinding, and fine grinding. C40 is a parameter that stores the final finished dimensions of the workpiece, C12 is a parameter that stores the final position of fine grinding feed as a deviation from the final finished dimension C40, and C1l is a parameter that stores the final position of rough grinding feed as Fi final finishing. The parameter C10 that is stored as a deviation from the dimension C40 is a parameter that stores the final position of rapid forwarding as a deviation from the rv 1% finished dimension C40. Further, B39 is a parameter for storing correction values for all stages, and C46 is a parameter for storing correction values unique to each stage. Those parameters are stored in the processed data storage area MDA as shown in FIG. N101
The data block of N102 is for rapid feed control, the data block of N10'3 is for midway stop control, the data block of N104 is for fine grinding feed control, the data block of N105 is for midway stop control, The data block N106 each represents fine grinding feed control. Therefore, when this program is executed, in the first step, the feeding of the grinding wheel is stopped after the completion of rough grinding and after the completion of fine grinding, so that the correction value can be set. The parameters of 839 and C46 above include:
The initial value O is set until the correction value is input and set. Therefore, if no correction value is input, machining is performed according to the originally set machining data shown in FIG. When the start switch S1 is pressed, the program shown in FIG. 4 is executed. At step 200, a read address counter ROC that controls reading of each data block of the numerical control program stored in the bubble cassette is set to an initial value of 1. Next, in step 202, first read-ahead inhibition flag BRIF is set.
is reset and set to a state where data can be pre-read into the buffer register BFI. Next, the process moves to step 204, and the data block input program shown in FIG. 3 is executed. FIG. 3 shows a program for inputting the numerical control program shown in FIG. 7 from the bubble cassette input/output device 34 to the buffer register BFI one data block at a time. This program is executed by interrupt processing using idle time of the CPU 21 while controlling the machine tool. BRI
F is a read-ahead prohibition flag, and when it is determined in step 100 that it is set, the process returns and the cheater block is not read into the buffer register. Step 102 is a step of determining the ROCF flag. When ROCF is in the set state, it indicates that reading of data from buffer register BFI to active register AR has been completed and buffer register BFI is in an empty state. On the other hand, when it is being reset,
Since the contents of the buffer register BFI have not yet been transferred to the active register AR, the process returns without reading any data. When the buffer register BF1 is empty, the process moves to step 104, and one data block of the numerical control program is input from the bubble cassette input/output device 34. Next, in step 106, a stop command code G65 is sent to stop the control of the machine tool in the middle of the data that has just been read.
It is determined whether or not it exists. If it is not the G65 stop instruction code, the process moves to step 112 and the data read from the bubble cassette input/output device 34 is transferred to the buffer register BFI. Thereafter, in step 114, the RO
The CF is reset, and in step 116, the content of the parameter ROC, which stores the read number of the next data block, is updated by 1. If the G65 code is present, the process moves to step 108, where the state of the switch designated by the command is determined. In the program shown in FIG. 7, the first stop instruction code exists at sequence number N103. The data block has "Pool", and this number represents the switch number. In this case, it is the switch 41. When that switch is on, the function of the stop command code is enabled, so the process moves to step 110 and the prefetch prohibition flag B
RIF is set. If the switch is off, the process proceeds to step 112 without setting the prefetch prohibition flag. In this way, data is input to the buffer register. Returning to step 206 in FIG. 4, the ROCF flag is determined, and when the input of data to the buffer register BFI is completed, steps 208 to 210 are performed. That is, as shown in FIG. 10, the contents of buffer register BF2 are transferred to active predesterator AR, and then the contents of buffer register BFI are transferred to buffer register BF2. In step 212, the instruction word of active register AR is read, and in step 214, the contents of buffer register BFI are read and the ROCF flag is set to indicate that it is empty. Then, in step 216, the command words of the numerical control program are decoded and executed. FIG. 5 is a flowchart showing the NC execution program. After decoding the data in steps 300, 302, and 304, if it is determined that the stop command code G65 exists, the process moves to step 306, where the state of the specified switch is determined, and if it is in the on state, the stop instruction code G65 is determined to exist. Since the instruction code is valid, the process moves to step 308 and control is stopped. At that time, the CPU 21 executes the correction value input program shown in FIG. When the switch is off, the stop command code is invalid. In the case of other command words, steps 312 to 320 are executed respectively, processing such as pulse distribution according to the command word is performed, and grinding wheel feed control is performed. After stopping the control, the operator presses the reverse switch S2 on the control panel 35.
Press . Then, pulse distribution is performed to move the grinding wheel backward by a certain amount, and the grinding wheel moves back by a certain amount and then stops. Thereafter, the operator operates the data writing device 36 to display the correction value input screen shown in FIG. 11 on the CRT 38.
Serve on top. This causes the CPU 21 to execute the program shown in FIG. Next, the operator measures the outer diameter of the workpiece. The progress state of the machining program is expressed as a grinding wheel stop position xO. From this data and measured values, correction values HO for all stages of finishing dimensions, correction values H1 to HIO for each stage, etc. are input. Their values are set as 839 in step 412 and as C46 in step 410.
is stored as. In this way, at the end of the rough grinding feed, it is possible to input the correction value necessary to correct the final finished dimension command value from the deviation between the actually measured outer diameter dimension of the workpiece and the command value. After inputting the correction data, the operator presses the forward switch s3. Then, pulse distribution is performed to send the grinding wheel to its original position when grinding was stopped, and the grinding wheel returns accurately to its original position. Thereafter, when the restart switch S4 is pressed, execution of the program starts from step 202 in FIG. The subsequent processing is as shown in N104 and N106 in Fig. 7. For fine grinding feed, the initial command value C40+C12 is B39.
Control is performed by correcting the correction value +C46, and fine grinding feed is controlled by correcting the initial final finishing command value C40 by the correction value B39+C46. As a result, the first workpiece can be machined to desired finished dimensions with high precision. As explained above, the stop command code can be inserted into any data block, and the determination of whether the function is valid or invalid can be controlled by the switch on the operation panel 35. In the first machining cycle of the program shown in Figure 7, a stop command code is inserted at the end of the rough grinding feed control and fine grinding feed control, but whether or not the machining is actually stopped is determined by each machining cycle. It is possible to control the time by setting the switch. In the above example, the input correction value of 1 corrects the feed end position of all subsequent grinding speed machining, but this also applies even if only the feed position of the final finishing machining is corrected. good.

【Effect of the invention】

The present invention provides a prefetch prohibition control unit that prohibits prefetching of data blocks, a stop control unit that stops the operation of a numerically controlled machine tool, and a correction of finished dimensions from intermediate machining dimensions based on the setting state of a switch means and a stop command code. The apparatus includes a correction value input section for inputting correction values necessary for the process, and a correction control section for restarting subsequent machining based on the corrected values. Therefore, the machine can be stopped in the middle of machining and the machining error can be determined from the difference between the actual machining dimensions and the theoretical machining dimensions.
Since the control of subsequent feed positions can be corrected based on the error and machining can be continued, the initial workpiece can be easily machined to desired finished dimensions. When stopping the device, the switch means is used to enable or disable the function of the stop command code, so when processing the next workpiece, the switch means disables the stop command code without changing the program. Just set it to the state,
Normal continuous processing is possible without pauses.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the concept of the present invention, Fig. 2 is a block diagram showing the configuration of a numerically controlled machine tool according to a specific embodiment of the present invention, and Fig. 3 is a block diagram showing the concept of the present invention. 4, 5, and 6 are flowcharts showing the processing procedure of the numerical control device, and FIG.
A diagram showing an example of a numerical control program, FIG. 8 is an explanatory diagram showing a grinding cycle, FIG. 9 is a data configuration diagram showing the configuration of the data area of the α device, and FIG. FIG. 11 is an explanatory diagram showing a method of reading data into a buffer register and an active register. FIG. 11 is an explanatory diagram showing a screen for inputting correction values. 10° Grinding machine 11'° Grinding wheel head G... Grinding wheel 13
Workpiece table 16.17°...Drive circuit 12.1
4゛・Servo motor 20・Numerical control device 22・Storage device 36 Data writing device 35° control panel 34・Bubble cassette input/output device Patent applicant Toyota Machinery Co., Ltd. Agent Patent attorney Osamu Fujitani 1−−−−−−−−−−−−−−−−−↓−
-----Figure 9Figure 10

Claims (3)

[Claims] (1) A machine tool that processes a workpiece with a tool, a drive device that drives a movable axis of the machine tool, a data storage device that stores data necessary to determine the feed position of the tool, and a storage medium. an input control unit that pre-reads the written data blocks of the numerical control program one block at a time into a buffer register; and an input control unit that transfers the data block input to the buffer register to the active register, decodes the command word of this data block, and reads the command word of the data block. a control unit that controls the driving device according to a command word and data set in a storage device; and a switch that enables a function of a stop command code that stops the operation of the numerically controlled machine tool. and the data storage device has an area for storing correction data for correcting the feed position of the tool, and the input control section stores one data block of the numerical control program written in the storage medium. When reading into the buffer register, the presence or absence of the stop command code and the set state of the switch means are determined, and as a result, it is determined that the stop command code is present and the set state of the switch means is the same as the stop command code. It has a prefetch prohibition control unit that prohibits prefetching of the next data block when it is determined that the function is enabled, and the control unit reads the instruction as a result of decoding the instruction word of the active register. a stop control section that stops the operation of the numerically controlled machine tool when the word is the stop command code and the setting state of the switch means is such that the function of the stop command code is enabled; a correction value input section for inputting a correction value necessary for correcting the finished dimensions of the workpiece into the data storage device while the operation is stopped; a correction control unit that outputs a command signal to the input control unit to start reading the data, corrects the feed position of the tool based on the correction value input to the data storage device, and restarts control of the machine tool; A numerically controlled machine tool characterized by having the following. (2) The numerically controlled machine tool according to claim 1, wherein the correction control section corrects the tool feed position for each feed step after restarting control based on the correction value. (3) The stop control section has a retraction means for retracting the tool by a certain amount after stopping machining, and the correction control section has an advance means for advancing the tool by the retracted amount at the start of control. A numerically controlled machine tool according to claim 1.